Simply because you've kept the default settings about which "warnings" you wanna see. I suppose if those warnings were switched off by default, that would be "less secure", since people are not made aware that nearly all websites except a few exceptions are transmitted unencrypted. You can see that also in other browsers, guess most have that little "lock" symbol in the status bar, right bottom corner.

Quotelilmisdot
why is the information sent in this browser unsecure because there's this window that keeps popping up saying the information you have sent is unencrypted!!!!!!.... why why why

All information is sent unencrypted by default in all browsers but the SSL/TLS websites connections. If the SSL/TLS layer is not activated in your browser's configuration, the SSL/TLS websites will not load and no connections will be allowed, nor will be stablished - blank page appears, error is notified. There is no security issue at all here. Simply unchek warnings. o.O

I have tried the suggestions given to no avail, the window keeps popping up and some of my friends have complained about the same problem. It's not exactly about security this time but the fact that it makes browsing a little boring!!!.